Re: TransWarp GS repair questions

[gbody4@bigpond.com]

Conrad,
I have looked through the TWGS self test code and the tests your card is failing on.

Changes between V1.5 & V1.8 rom means the tests that have been failing will always pass on a V1.8 Rom.

Speed Control 0503
Interrupt Logic 0601
Slot Slowdown 0701
 

These tests use specific timing loops and allow for a small range variation in the result in V1.5, V1.8 runs the test but doesn't check the result. I would guess AE disabled the result check as people were starting to use higher speed oscillators. It would have been easier than having to produce a new Rom version for each Oscillator speed.

Testing with the V1.8 rom appears to only validate that the IIgs is running correctly at either slow (1MHz) or normal speed (2.8MHz) only.


I would guess that if your card was ok, then you would need the correct speed Ocsillator for your card to pass the tests with your version of the rom.

I would test your card with a V1.8 rom or you could try turning on the TWGS via a small bit of machine code.

JSL BCFF0C - Reset TWGS to config set by control panel
JSL BCFF30 - Flush cache
JSL BCFF48 - enable Data cache
JSL BCFF10 - Get max speed
JSL BCFF24 - Set Current speed
RTS

300:22 0c ff bc 22 30 ff bc 22 48 ff bc 22 10 ff bc 22 24 ff bc 60

You should be able to bypass/disable running the TWGS by pressing just the option key at startup/reset.
 
Geoff